Files
py-media-grader/croppa/tracking.py

150 lines
6.3 KiB
Python

from typing import List, Dict, Tuple, Optional
class MotionTracker:
"""Handles motion tracking for crop and pan operations"""
def __init__(self):
self.tracking_points = {} # {frame_number: [(x, y), ...]}
self.tracking_enabled = False
self.base_crop_rect = None # Original crop rect when tracking started
self.base_zoom_center = None # Original zoom center when tracking started
def add_tracking_point(self, frame_number: int, x: int, y: int):
"""Add a tracking point at the specified frame and coordinates"""
if frame_number not in self.tracking_points:
self.tracking_points[frame_number] = []
self.tracking_points[frame_number].append((x, y))
def remove_tracking_point(self, frame_number: int, point_index: int):
"""Remove a tracking point by frame and index"""
if frame_number in self.tracking_points and 0 <= point_index < len(self.tracking_points[frame_number]):
del self.tracking_points[frame_number][point_index]
if not self.tracking_points[frame_number]:
del self.tracking_points[frame_number]
def clear_tracking_points(self):
"""Clear all tracking points"""
self.tracking_points.clear()
def get_tracking_points_for_frame(self, frame_number: int) -> List[Tuple[int, int]]:
"""Get all tracking points for a specific frame"""
return self.tracking_points.get(frame_number, [])
def has_tracking_points(self) -> bool:
"""Check if any tracking points exist"""
return bool(self.tracking_points)
def get_interpolated_position(self, frame_number: int) -> Optional[Tuple[float, float]]:
"""Get interpolated position for a frame based on tracking points"""
if not self.tracking_points:
return None
# Get all frames with tracking points
frames = sorted(self.tracking_points.keys())
if not frames:
return None
# If we have a point at this exact frame, return it
if frame_number in self.tracking_points:
points = self.tracking_points[frame_number]
if points:
# Return average of all points at this frame
avg_x = sum(p[0] for p in points) / len(points)
avg_y = sum(p[1] for p in points) / len(points)
return (avg_x, avg_y)
# If frame is before first tracking point
if frame_number < frames[0]:
points = self.tracking_points[frames[0]]
if points:
avg_x = sum(p[0] for p in points) / len(points)
avg_y = sum(p[1] for p in points) / len(points)
return (avg_x, avg_y)
# If frame is after last tracking point
if frame_number > frames[-1]:
points = self.tracking_points[frames[-1]]
if points:
avg_x = sum(p[0] for p in points) / len(points)
avg_y = sum(p[1] for p in points) / len(points)
return (avg_x, avg_y)
# Find the two frames to interpolate between
for i in range(len(frames) - 1):
if frames[i] <= frame_number <= frames[i + 1]:
frame1, frame2 = frames[i], frames[i + 1]
points1 = self.tracking_points[frame1]
points2 = self.tracking_points[frame2]
if not points1 or not points2:
continue
# Get average positions for each frame
avg_x1 = sum(p[0] for p in points1) / len(points1)
avg_y1 = sum(p[1] for p in points1) / len(points1)
avg_x2 = sum(p[0] for p in points2) / len(points2)
avg_y2 = sum(p[1] for p in points2) / len(points2)
# Linear interpolation
t = (frame_number - frame1) / (frame2 - frame1)
interp_x = avg_x1 + t * (avg_x2 - avg_x1)
interp_y = avg_y1 + t * (avg_y2 - avg_y1)
return (interp_x, interp_y)
return None
def get_tracking_offset(self, frame_number: int) -> Tuple[float, float]:
"""Get the offset to center the crop on the tracked point"""
if not self.tracking_enabled or not self.base_zoom_center:
return (0.0, 0.0)
current_pos = self.get_interpolated_position(frame_number)
if not current_pos:
return (0.0, 0.0)
# Calculate offset to center the crop on the tracked point
# The offset should move the display so the tracked point stays centered
offset_x = current_pos[0] - self.base_zoom_center[0]
offset_y = current_pos[1] - self.base_zoom_center[1]
return (offset_x, offset_y)
def start_tracking(self, base_crop_rect: Tuple[int, int, int, int], base_zoom_center: Tuple[int, int]):
"""Start motion tracking with base positions"""
self.tracking_enabled = True
self.base_crop_rect = base_crop_rect
self.base_zoom_center = base_zoom_center
def stop_tracking(self):
"""Stop motion tracking"""
self.tracking_enabled = False
self.base_crop_rect = None
self.base_zoom_center = None
def to_dict(self) -> Dict:
"""Convert to dictionary for serialization"""
return {
'tracking_points': self.tracking_points,
'tracking_enabled': self.tracking_enabled,
'base_crop_rect': self.base_crop_rect,
'base_zoom_center': self.base_zoom_center
}
def from_dict(self, data: Dict):
"""Load from dictionary for deserialization"""
# Convert string keys back to integers for tracking_points
tracking_points_data = data.get('tracking_points', {})
self.tracking_points = {}
for frame_str, points in tracking_points_data.items():
frame_num = int(frame_str) # Convert string key to integer
self.tracking_points[frame_num] = points
self.tracking_enabled = data.get('tracking_enabled', False)
self.base_crop_rect = data.get('base_crop_rect', None)
self.base_zoom_center = data.get('base_zoom_center', None)